Side-by-side technical and economic comparison between Anthropic's Claude Fable 5.1 and DeepSeek's DeepSeek-V4.1-Reasoner.
| Metric | Claude Fable 5.1 | DeepSeek-V4.1-Reasoner | Advantage |
|---|---|---|---|
| Provider Organization | Anthropic | DeepSeek | — |
| Standard Input / 1M | $10.00 | $0.28 | DeepSeek-V4.1-Reasoner (97% lower) |
| Cached Input / 1M | $0.25 | $0.028 | DeepSeek-V4.1-Reasoner lower |
| Output / 1M | $50.00 | $0.42 | DeepSeek-V4.1-Reasoner lower |
| Context Window | 1M | 256k | Claude Fable 5.1 (1M) |
| Max Generation Tokens | 32k | 384k | DeepSeek-V4.1-Reasoner |
| Tokenizer Family | Anthropic Claude BPE (~65k vocabulary) | DeepSeek Byte-Level BPE (102k vocabulary) | — |
| Workload (per month) | Claude Fable 5.1 | DeepSeek-V4.1-Reasoner |
|---|---|---|
| Chatbot10k requests · 500 in / 200 out | $150.00 | $2.24 |
| RAG app100k requests · 8,000 in / 1,200 out | $14,000.00 | $274.40 |
| Coding agent100k requests · 12,000 in / 2,000 out | $22,000.00 | $420.00 |
Standard rates, no caching or batch discounts. Model your own numbers below.
Opt for Claude Fable 5.1 when your engineering requirements prioritize Anthropic's ecosystem, specific tokenizer efficiencies (Calibrated Claude Tokenizer (±3%)), or when your expected prompt-to-completion ratios favor its $10/M input rate.
Opt for DeepSeek-V4.1-Reasoner when looking for DeepSeek's tooling integration, specific context window depth (256k tokens), or when output generation volume favors its $0.42/M rate.
At a typical 3:1 input-to-output token mix, DeepSeek-V4.1-Reasoner is about 98% cheaper than Claude Fable 5.1. Claude Fable 5.1 costs $10 per 1M input and $50 per 1M output tokens; DeepSeek-V4.1-Reasoner costs $0.28 and $0.42.
Claude Fable 5.1 has the larger context window: 1M tokens vs 256k.
Claude Fable 5.1: yes, cached input costs $0.25/1M. DeepSeek-V4.1-Reasoner: yes, cached input costs $0.028/1M.